Residency · Residency · Rheumatology
Sjogren Syndrome
Introduction
Sjogren syndrome is a chronic autoimmune disease that primarily targets the exocrine glands, particularly the salivary and lacrimal glands, but is increasingly recognized as a systemic disease with manifestations extending far beyond sicca symptoms. Primary Sjogren syndrome occurs in isolation, while secondary Sjogren syndrome is associated with another connective tissue disease such as rheumatoid arthritis, systemic lupus erythematosus, or systemic sclerosis. The prevalence is estimated at 0.5 to 1 percent of the general population, with a striking female-to-male ratio of 9 to 1 and a peak onset between 40 and 60 years of age. Systemic manifestations occur in 30 to 40 percent of patients and are the primary drivers of morbidity. A distinctive feature of Sjogren syndrome is the 5 to 10 percent lifetime risk of B cell non-Hodgkin lymphoma, the highest lymphoma risk of any autoimmune disease.
Pathogenesis
The pathogenesis of Sjogren syndrome is centered on the concept of epithelitis, in which salivary and lacrimal epithelial cells serve as both targets and active participants in the autoimmune process. Innate immune activation features a type I interferon signature, activation of Toll-like receptors by endogenous nucleic acids, and overexpression of B-cell activating factor (BAFF). The adaptive immune response is characterized by focal lymphocytic sialadenitis, with T and B cell infiltration of salivary glands and the formation of ectopic germinal center-like structures that sustain local autoantibody production. The hallmark autoantibodies, anti-Ro/SSA and anti-La/SSB, target RNA-binding proteins, though their direct pathogenic role remains debated. Genetic susceptibility involves HLA-DRB1*03:01, STAT4, IRF5, BLK, and TNFAIP3 risk loci. Environmental triggers, particularly Epstein-Barr virus and HTLV-1, may initiate disease through molecular mimicry mechanisms.
Diagnosis
2016 ACR/EULAR Classification Criteria
The 2016 ACR/EULAR classification criteria are applicable to patients with at least one symptom of ocular or oral dryness. A score of 4 or greater classifies a patient as having primary Sjogren syndrome. The highest-weighted items are labial salivary gland biopsy demonstrating focal lymphocytic sialadenitis with a focus score of 1 or greater, defined as at least one focus of 50 or more lymphocytes per 4 square millimeters, which receives 3 points, and anti-SSA/Ro positivity, which also receives 3 points. Lower-weighted items include an ocular staining score of 5 or greater (1 point), a Schirmer test of 5 millimeters or less in 5 minutes (1 point), and an unstimulated salivary flow rate of 0.1 milliliters per minute or less (1 point). The criteria achieve a sensitivity of 96 percent and specificity of 95 percent. Important exclusion criteria include a history of head and neck radiation, hepatitis C infection, AIDS, sarcoidosis, amyloidosis, graft-versus-host disease, and IgG4-related disease.
| Criterion | Finding | Points |
|---|---|---|
| Labial salivary gland biopsy | Focal lymphocytic sialadenitis, focus score ≥1 | 3 |
| Anti-SSA/Ro positivity | Positive | 3 |
| Ocular staining score | ≥5 (or van Bijsterveld ≥4) | 1 |
| Schirmer test | ≤5 mm / 5 minutes | 1 |
| Unstimulated salivary flow rate | ≤0.1 mL/min | 1 |
| Classification threshold | Score ≥4 |
Key Diagnostic Tests
Anti-Ro/SSA antibodies are present in 60 to 75 percent of patients with primary Sjogren syndrome and exist as two subtypes: Ro52 (also known as TRIM21), which is less specific and seen in myositis, SLE, and ILD, and Ro60, which is more specific for Sjogren syndrome and SLE. Anti-La/SSB antibodies are present in 30 to 40 percent and are almost always accompanied by anti-Ro; they are associated with milder disease. Antinuclear antibodies are positive in approximately 80 percent of patients, typically in a speckled pattern. Rheumatoid factor is positive in 50 to 60 percent. Hypergammaglobulinemia, reflecting polyclonal B cell activation with IgG elevation, is common. Low complement levels, particularly C3 and C4, are associated with systemic disease and increased lymphoma risk. Cryoglobulins of mixed type II are associated with vasculitis and lymphoma risk.
Salivary Gland Assessment
Minor salivary gland biopsy, obtained through a lip biopsy procedure, remains the gold standard for histologic diagnosis, with a focus score of 1 or greater being the diagnostic threshold; the presence of germinal center-like structures should also be assessed, as these predict more aggressive disease. Salivary gland ultrasound has emerged as an increasingly important non-invasive alternative, demonstrating inhomogeneous parenchyma with hypoechoic and anechoic areas in affected glands. The OMERACT scoring system provides standardized grading from 0 to 3 for each gland. Sialometry measures unstimulated whole salivary flow, with less than 0.1 milliliters per minute being abnormal. Scintigraphy and sialography have been largely replaced by ultrasound in contemporary practice.
Ocular Assessment
The Schirmer test involves placing a filter paper strip in the lower conjunctival fornix, with less than 5 millimeters of wetting in 5 minutes being abnormal. Ocular surface staining using lissamine green for the conjunctiva and fluorescein for the cornea is graded by the Oxford or SICCA scoring systems. Tear break-up time of less than 10 seconds is abnormal and reflects tear film instability. Rose Bengal staining, which was formerly widely used, has been largely replaced by lissamine green due to its better tolerability.
<image>A diagnostic workup diagram for Sjogren syndrome. Show a central patient figure with arrows pointing to five diagnostic modalities: (1) Serology panel showing anti-Ro/SSA, anti-La/SSB, ANA, RF, complement levels, cryoglobulins, immunoglobulins with expected findings in SS. (2) Labial salivary gland biopsy with a microscopic illustration showing focal lymphocytic sialadenitis with a focus of >50 lymphocytes per 4mm² and a focus score calculation. (3) Ocular testing showing Schirmer test (filter paper in lower eyelid) and ocular surface staining with lissamine green showing punctate staining. (4) Salivary gland ultrasound showing inhomogeneous parotid gland with multiple hypoechoic areas. (5) Sialometry showing collected saliva measurement. List the 2016 ACR/EULAR criteria point values next to each relevant test.</image>
Clinical Manifestations
Sicca Symptoms
Xerophthalmia, or dry eyes, manifests as a gritty or sandy sensation, foreign body sensation, burning, and photosensitivity. Severe dry eye progresses to keratoconjunctivitis sicca with the potential for corneal erosions. Xerostomia, or dry mouth, produces difficulty swallowing dry food, increased dental caries, oral candidiasis, and angular cheilitis. Parotid gland enlargement occurs in 25 to 60 percent of patients and is typically bilateral; unilateral or rapidly enlarging parotid swelling should raise concern for lymphoma. Dryness may also affect the vaginal mucosa, nasal passages, skin (xeroderma), and tracheobronchial tree (xerotrachea presenting as a dry cough).
Systemic Manifestations
Musculoskeletal involvement is the most common systemic manifestation, presenting as polyarthralgia, non-erosive symmetric polyarthritis, and myalgia. Pulmonary disease includes interstitial lung disease with NSIP being the most common pattern and lymphocytic interstitial pneumonia being characteristic though rare, as well as airway disease including bronchiolitis and bronchiectasis. Renal involvement classically manifests as tubulointerstitial nephritis causing type 1 renal tubular acidosis with hypokalemia, while glomerulonephritis including membranoproliferative and cryoglobulinemic forms occurs less frequently. Neurologic manifestations include peripheral neuropathy with sensory predominance, including small fiber, trigeminal, and autonomic neuropathies, while central nervous system involvement remains controversial but may present with MS-like lesions or myelitis. Cutaneous manifestations encompass purpura reflecting small vessel vasculitis, including hypergammaglobulinemic purpura of Waldenstrom, annular erythema, and urticarial vasculitis. Hematologic complications include cytopenias, cryoglobulinemia, and hypergammaglobulinemia. Gastrointestinal involvement includes dysphagia, atrophic gastritis, and hepatobiliary disease including overlap with primary biliary cholangitis and autoimmune hepatitis. Fatigue is often the most debilitating symptom for patients and is frequently disproportionate to objective disease findings.
Lymphoma Risk
The lifetime risk of B cell non-Hodgkin lymphoma in Sjogren syndrome is 5 to 10 percent, representing a 15- to 20-fold increased relative risk compared to the general population. The most common type is marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) of the salivary glands. Risk factors for lymphoma development include persistent parotid gland swelling, low C4, cryoglobulinemia, palpable purpura or vasculitis, lymphadenopathy, CD4 lymphopenia, and high ESSDAI scores. Monitoring involves regular clinical assessment with consideration of PET-CT imaging when suspicious features develop.
Disease Activity Assessment
Disease activity in Sjogren syndrome is assessed using the EULAR Sjogren Syndrome Disease Activity Index (ESSDAI), which encompasses 12 domains including constitutional, lymphadenopathy, glandular, articular, cutaneous, pulmonary, renal, peripheral nervous system, central nervous system, muscular, hematological, and biological manifestations, with weights ranging from 1 to 6 per domain. The EULAR Sjogren Syndrome Patient Reported Index (ESSPRI) captures the patient perspective by measuring dryness, pain, and fatigue on 0 to 10 scales, with the mean score providing a composite assessment. The ClinESSDAI variant excludes the biological domain for a purer clinical activity measure.
Management
Sicca Symptom Management
For dry eyes, artificial tears should be preservative-free when used more than 4 times daily. Topical anti-inflammatory agents including cyclosporine 0.05 percent (Restasis) and lifitegrast 5 percent (Xiidra) take 4 to 8 weeks to achieve their full effect. Punctal plugs reduce tear drainage and are effective for moderate to severe dry eye. Autologous serum tears are reserved for refractory cases. Secretagogues including pilocarpine at 5 milligrams three to four times daily and cevimeline at 30 milligrams three times daily are muscarinic agonists that stimulate residual gland function. For dry mouth, frequent water sips, sugar-free gum, and lozenges provide symptomatic relief. Pilocarpine and cevimeline at the same doses benefit both ocular and oral dryness, with sweating and gastrointestinal upset as the main side effects. Fluoride treatments and regular dental care are essential to prevent the accelerated dental caries that result from reduced salivary flow. Oral candidiasis should be treated with nystatin or fluconazole.
Systemic Disease Management
Hydroxychloroquine is widely used for arthralgias, fatigue, and mild systemic features, though the evidence base is limited; the JOQUER trial failed to meet its primary endpoint of ESSPRI improvement but may benefit articular symptoms. Methotrexate is used for inflammatory arthritis. Mycophenolate mofetil is employed for ILD, glomerulonephritis, and cytopenias. Azathioprine serves as an alternative for cytopenias and systemic disease. Rituximab was evaluated in the TRACTISS trial, which was negative for its primary endpoints of oral dryness and fatigue, but rituximab remains used in practice for severe extraglandular manifestations including vasculitis, cytopenias, ILD, and cryoglobulinemia. Belimumab showed improvement in ESSDAI in the BELISS open-label study, and a Phase III trial (BELIZE) is underway. Glucocorticoids are reserved for severe systemic disease such as vasculitis, ILD, and neuropathy, and should be avoided for sicca symptoms alone. Ianalumab, an anti-BAFF receptor antibody, is in Phase III trials with promising early data.
<image>A comprehensive clinical overview illustration of Sjogren syndrome showing a female figure with labeled arrows pointing to all major organ manifestations. Head: Dry eyes with keratoconjunctivitis sicca, dry mouth with dental caries and oral candidiasis, bilateral parotid gland enlargement. Lungs: ILD (NSIP pattern), bronchiectasis. Kidneys: Tubulointerstitial nephritis with Type 1 RTA. Joints: Non-erosive symmetric polyarthritis of hands. Skin: Palpable purpura on lower extremities. Peripheral nerves: Sensory neuropathy in stocking-glove distribution. Include an inset box showing the lymphoma risk factors (low C4, cryoglobulins, parotid swelling, purpura) with an arrow pointing to marginal zone (MALT) lymphoma. Use a clean medical illustration style.</image>
Key Clinical Pearls
- Low C4 + cryoglobulinemia + parotid swelling + purpura = highest risk for lymphoma transformation
- Pilocarpine and cevimeline require residual glandular function to be effective; they do not work in end-stage gland destruction
- Anti-Ro/SSA antibodies can cause neonatal lupus (congenital heart block); screen all SS women of childbearing age
- Type 1 RTA (distal) with hypokalemia and nephrocalcinosis is the characteristic renal lesion of SS
- Fatigue is the most disabling symptom for patients and is often inadequately addressed
- The 2016 criteria do NOT require both dry eyes and dry mouth; only one symptom of dryness is needed as entry criterion
References
- Shiboski CH, et al. 2016 ACR-EULAR Classification Criteria for Primary Sjogren's Syndrome. Arthritis Rheumatol. 2017;69(1):35-45.
- Ramos-Casals M, et al. EULAR recommendations for the management of Sjogren's syndrome with topical and systemic therapies. Ann Rheum Dis. 2020;79(1):3-18.
- Nocturne G, Mariette X. Advances in understanding the pathogenesis of primary Sjogren's syndrome. Nat Rev Rheumatol. 2013;9(9):544-556.
- Bowman SJ, et al. Randomized controlled trial of rituximab and cost-effectiveness analysis in treating fatigue and oral dryness in primary Sjogren's syndrome (TRACTISS). Arthritis Rheumatol. 2017;69(7):1440-1450.
- Quartuccio L, et al. BLyS upregulation in Sjogren's syndrome associated with lymphoproliferative disorders. Ann Rheum Dis. 2013;72(12):2020-2023.
